铁芯损耗与铁芯磁通密度B的关系为（   ）。

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69398' and id < 4492757 and id<>'4492757' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku_ where sourceid='69398' and id > 4492757 and id<>'4492757' order by id asc limit 5